PN 88300150
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The MT2834MR stores its configuration parameters and S-Register values in its nonvolatile memory. The
&W0 command stores current parameters and values in its nonvolatile RAM. This command also sets the
modem so that on power up, or when reset with an ATZ command, the modem reads all its configuration
and S-Register parameters from RAM, and not from the factory settings in ROM. The &W command
changes the configuration parameters stored in RAM that you specifically intend to alter. All other default
parameters remain unchanged.
The &W1 command sets the modem so that it does not store parameters to RAM and, on power up or
when an ATZ command is entered, parameters are read from the factory default settings in ROM.
Before using the &W command, view the modem’s current operating parameters. Use the L5, L6, and L7
commands to display the current modem configuration.
4.4
Summary
V.42 error correction is built into the MT2834MR's hardware, detecting and correcting virtually 100% of
transmission errors (usually caused by noisy phone lines). When errors are detected, the V.42 protocol
causes the modem to retransmit the data block in which the error was found.
V.42bis and MNP 5 data compression features are built into the MT2834MR's hardware, providing a
higher data throughput than the modem’s modulation speed. The throughput increase depends on the
type of data transmitted.
The MT2834MR also supports ITU-T Group 3/EIA TR-29 Class 2 fax operation. This enables the modem
to send and receive text, graphics, and images to and from any Group 3 fax machine.
The MT2834MR is set for one of three different modes of operation, along with activating data
compression in Reliable mode. Normal mode (&E0) disables error correction, Reliable mode (&E2) turns
it on, and Auto-Reliable mode (&E1) lets the modem automatically turn V.42 on when it detects its use in
another modem.
Flow control methods are used by the MT2834MR to prevent data loss from buffer overflow. The modem
both initiates flow control and responds to pacing, using either Xon/Xoff commands or RS232C/V.24
signaling via CTS (from the modem) or RTS (from the computer/terminal). Hewlett-Packard ENQ/ACK is
also supported. If needed, Xon/Xoff commands are passed through the modem to a remote computer or
terminal.
The MT2834MR's speed conversion feature lets the modem operate at one speed over the telephone line
and another speed over the RS232C/V.24 serial port. This lets the computer communicate with the
modem at a fixed speed of up to 115,200 bps, while the modem operates at various rates of up to 28,800
bps (V.34 enabled). This ability is vital for data compression, since your computer must send data to the
modem at a higher speed than the rate at which the modem is sending data over the phone line.